Repair-It

BMW says this fluid is 'lifetime' like the manual trans and power steering. I've replaced the other two and this is the last OEM fluid in the car, so time to change it. Like most independent rear differentials in most German and Japanese stuff, this diff has both a drain and a fill plug, making it much more convenient and less messy to do this job than on, say, a Fleetwood.

I ensured all images were taken in landscape mode this time, but I still have the same "It was not possible to determine the dimensions of the image. Please verify that the URL you entered is correct." error. Maybe I'll download them from OneDrive via the web interface and retry? Kevin, for reference, I'm uploading from the One Drive Camera Roll folder where the images are 'online only'. But even after triggering a download, the same error is shown. Maybe some incompatible metadata from viewing via file explorer?

Interesting. Even after downloading from One Drive (via multi-image ZIP file), still seeing the same error. Maybe I have to email to Kevin and have him upload? Not terribly convenient. Also confirmed it isn't an HDR/non-HDR issue as images of both types have the same error. There otherwise doesn't appear to be anything special about the image (12MP, 4032x3024). Where do I file a support ticket?

Yeah it's nice not to have to remove the rear cover like a B-body. I feel like with an open diff the fluid could be lifetime because not much is going on in there as long as dirt didn't get in. With a limited slip, that's a different thing entirely and I think it needs to be changed regularly.

On the picture thing, maybe I should just use this issue as an excuse to update the forum version again.

Pictures are working! Here is the diff as viewed from the rear RH side: The original drain/fill plugs use metal gaskets. FCP Euro has replacements that have integrated o-rings for your convenience. The BMW fluid is very expensive. Conveniently, Red Line makes some gear oil that's compatible with the spec. The capacity is 0.9qt, however, since you need to use a transfer pump to get it into the diff getting all that oil out of the quart bottle is tough so the internet recommends getting 2qt. My transfer pump is terrible so it leaked plenty during the transfer so it was good to have 2. Regardless, fill it until it comes back out the fill plug then you're GTG. The oil that came out was barely dirty looking, but whatever, this job is easy and the rear of the car was up to do the shocks anyways. I'll save the rest for when I change the fluid again in 20 years.

What's the deal with the pictures? I drag them from OneDrive camera roll as online only all the time and never have any issues (using my laptop).

The 85W-90 fluid I used in my E55 is GL-5 and I noticed all my other stuff (75W-90 and 80W-90) is also GL-5. Is there another spec?

This is GL5. The BMW spec is SAF-XO.

This is all my owner's manual says.
Other than the oddball viscosity I can probably use most fluids. And I could probably use 75W or 80W-90...but I used the 85W-90.